Double Membrane Organelles — NEET Biology

Correct answer: A — S1, S2 and S3

The core concept tested is the structural and functional similarities and differences between mitochondria and chloroplasts, particularly their semi-autonomous nature. Let's evaluate each statement: S1: This statement is correct. Both mitochondria and chloroplasts are described as double membrane-bound structures, and mitochondria are explicitly stated to divide by fission (NCERT Page 97, 98). Division by fission is generally applicable to both semi-autonomous organelles. S2: This statement is incorrect. The NCERT text states that 'the inner chloroplast membrane is relatively less permeable' (NCERT Page 98), but it does not make this claim for the inner mitochondrial membrane in comparison to its outer membrane. S3: This statement is incorrect. Chlorophyll pigments are present in the thylakoids, not the stroma, of chloroplasts (NCERT Page 98). Enzymes for aerobic respiration are indeed in the mitochondrial matrix and inner membrane, but the first part of the statement is false. S4: This statement is correct. Both organelles possess their own single circular DNA molecules, RNA molecules, and 70S ribosomes, enabling them to synthesize some of their proteins, hence referred to as semi-autonomous (NCERT Page 97-98). S5: This statement is correct. The cristae in mitochondria are infoldings of the inner membrane that increase the surface area for aerobic respiration (NCERT Page 97). Thylakoids, arranged in stacks (grana), provide the surface area for light-dependent reactions of photosynthesis (NCERT Page 98). Based on the evaluation, statements S1, S4, and S5 are correct. Therefore, option B is the correct answer. This question comprehensively tests the distinctive features shared by mitochondria and chloroplasts, including their membranes, genetic material, ribosomes, and roles in increasing surface area.